java - 为什么是 Class.newInstance() "evil"？

Question

Ryan Delucchi问 here在评论 #3 到 Tom Hawtin的答案:

why is Class.newInstance() "evil"?

这是对代码示例的响应:

// Avoid Class.newInstance, for it is evil.
Constructor<? extends Runnable> ctor = runClass.getConstructor();
Runnable doRun = ctor.newInstance();

那么，为什么它是邪恶的？

Answer 1

Java API 文档解释了原因(http://java.sun.com/javase/6/docs/api/java/lang/Class.html#newInstance()):

Note that this method propagates any exception thrown by the nullary constructor, including a checked exception. Use of this method effectively bypasses the compile-time exception checking that would otherwise be performed by the compiler. The Constructor.newInstance method avoids this problem by wrapping any exception thrown by the constructor in a (checked) InvocationTargetException.

换句话说，它可以击败检查异常系统。